The number of measles cases in the U.S. has surpassed the record-breaking tally for all of 2025, with five more months of 2026 still to come. The U.S. Centers for Disease Control and Prevention logged 2,318 cases of measles as of Thursday, according to an agency update on Friday. The nation had 2,289 cases in 2025, the worst year for measles in more than three decades. The U.S. eliminated local measles spread in 2000 by maintaining high vaccination rates, which have fallen in recent years to below the 95% coverage needed to prevent outbreaks. Measles cases are undercountedWhile measles cases in the U.S. are climbing, it may be impossible to say exactly how far-reaching the spread is.